JP2687399B2 - Television multiplex broadcast receiver - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a television teletext receiver.

[Summary of the Invention]

The present invention relates to a television teletext receiver,
When a teletext image is displayed, the usability is improved by invalidating the channel preset.

[Conventional technology]

A TV teletext (hereinafter referred to as teletext) receiver has a built-in type that has a teletext decoder in the TV receiver. From this built-in type, the CRT display and speaker are omitted, and the video output and audio output are There are a stand-alone adapter that can be obtained and a connection adapter that externally attaches a teletext decoder to a television receiver.

FIG. 3 shows an example of the built-in receiver,
In the figure, (1) shows an electronic tuning type tuner circuit, and the video intermediate frequency signal from the tuner circuit (1) is supplied to a video detection circuit (3) through a video intermediate frequency amplifier (2) to perform teletext broadcasting. The color video signal Sc with the signal is demodulated.

When the television broadcast is viewed, this signal Sc is supplied to the Y / C processing circuit (5) through the television broadcast side contact T of the switch circuit (4), and the three primary color signals T of red, green and blue are transmitted.
r, Tg, Tb are taken out, and these signals Tr to Tb are supplied to the color picture tube (7) through the contact point T on the television broadcasting side of the switch circuit (6).

At this time, the processing circuit (5) extracts the synchronizing pulse Ps from the signal Sc, supplies the pulse Ps to the deflection circuit (8) to form a deflection signal, and the signal is deflected by the picture tube (7). It is supplied to the coil (9).

Therefore, the picture tube (7) has a tuner circuit (1).
The image of the television broadcast of the channel selected in is displayed.

On the other hand, at the time of viewing the teletext, the signal Sc from the wave receiving circuit (3) is supplied to the teletext decoder (11) to decode the three primary color signals Mr, Mg, Mb of red, green and blue in the teletext, These signals Mr to Mb are supplied to the picture tube (7) through the teletext-side contacts M of the switch circuit (6).

Further, a synchronization pulse Ps is formed in the decoder (11), and this pulse Ps is supplied to the deflection circuit (8) through the teletext-side contact M of the switch circuit (4) and further through the processing circuit (5) for deflection. A signal is formed and this signal is supplied to the deflection coil (9).

The switch circuits (4) and (6) are connected to the decoder (1
It is controlled by the control signal Sw from 1).

Therefore, the tuner circuit (1) and the decoder (11)
By controlling the, it is possible to receive and display an arbitrary channel and program of the tele broadcast and the teletext.

A system controller (21) for controlling the system controller is constituted by a microcomputer, and various control signals St, Sm are supplied to the tuner circuit (1) and the decoder (7). Further, an operation key (switch) (22) for changing the channel, volume, etc. is connected to the syscon (21), and a synchronization pulse Ps is supplied from the deflection circuit (8) to the syscon (21). .

Therefore, by operating the key (22), an arbitrary television broadcast or text broadcast can be viewed.

[Problems to be solved by the invention]

By the way, in such a receiver, when presetting the reception channel, the preset key (22P) of the keys (22) is pressed to enter the preset mode.

Then, according to the signal St, the reception frequency of the tuner circuit (1) gradually rises as shown in FIG. 4A, that is, the reception frequency is scanned.

Then, during this scan, if television broadcasting is being performed on channels 4, 6 and 8 as indicated by thick lines in FIG. A, as shown in B in FIG. , 8
Sync pulse to syscon (21) when it becomes a channel
Ps will be supplied.

Therefore, in the syscon (21), the presence or absence of the synchronization pulse Ps is detected while scanning the reception frequency, and when the synchronization pulse Ps changes from yes → no → yes, for example, the reception frequency changes from channel 4 to channel 4. When changing from channel 5 to channel 6, the scanning is stopped on the channel 6 and the AFT operation is performed so that the channel 6 is positively tuned.

Then, if you press any channel key (22N) of the keys (22), the sixth channel is received at the memory address (memory address of syscon (21)) corresponding to this key (22N). The data of the signal St when it is present is stored. In addition, the preset mode of the receiver is released and the receiver enters the normal operation mode.

Therefore, by repeating the above operations and operations, an arbitrary channel is preset in the channel key (22N).

After that, by simply pressing the channel key (22N), the channel registered in that key is selected.

However, in such a receiver, when the preset operation of the above-mentioned channel is performed in the teletext display mode, the synchronization pulse Ps formed in the decoder (11) at this time regardless of the reception frequency. But,
Switch circuit (4) → processing circuit (5) → deflection circuit (8)
Since it is continuously supplied to the syscon (21) through, the scan of the reception frequency will not stop. Or,
The data of the preset channels will be cleared.

Then, such a trouble occurs as long as the receiver detects the channel in which broadcasting is being performed based on the presence or absence of the synchronization pulse Ps.

The present invention is intended to solve such a problem.

[Means for solving the problem]

Therefore, in the present invention, a part of the program of the syscon (21) is configured as shown in the flowchart of FIG. 1, for example.

[Action]

In the teletext display mode, channel presetting is prohibited.

〔Example〕

In FIG. 1, step (31) is a step for accepting the input of the key (22), and the key input is waited in step (31) until the key input is performed.

Then, when a key input is performed, the process proceeds to step (3).
Go to 2), and in this step (32), go to step (3
It is checked whether the key input in 1) is the preset key (22P). If it is the preset key (22P), the process proceeds from step (32) to step (33), and in this step (33) It is checked whether the current display mode is the teletext display mode, and if it is not the teletext display mode (including the mode in which the image of the teletext is superimposed on the screen of the television broadcast), the processing is performed. Is from step (33) to step (3
Proceeding to 4), the above-mentioned channel preset processing is performed in this step (34), and when this preset processing ends, the processing returns to step (31) and waits for key input again.

However, in the teletext display mode in step (33), the process returns to step (31) without executing steps (33) to (34), and the preset process of step (34) is prohibited. It

When the key input in step (31) is other than the preset key (22P) in step (32), the process proceeds from step (32) to step (40). After the processing corresponding to the key input is performed, the process returns to step (31).

Thus, according to the present invention, even if the preset key (22P) of the channel is pressed in the teletext display mode, the preset of the channel is prohibited or ignored, so that the trouble that the scanning does not stop does not occur. . Alternatively, the data of the already preset channel will not be cleared.

Moreover, the structure for that purpose only needs to change a part of the software in the syscon (21), and the cost does not increase.

In the example shown in FIG. 2, when it is determined in step (33) that the teletext display mode is selected, the television broadcast display mode is switched to in step (35), and then the preset process is performed in step (34). This is the case.

〔The invention's effect〕

According to the present invention, in the teletext display mode, even if the preset key (22P) of a channel is pressed, presetting of the channel is prohibited or ignored, so that the trouble that the scanning does not stop does not occur.
Alternatively, the data of the already preset channel will not be cleared.

Moreover, the structure for that purpose only needs to change a part of the software in the syscon (21), and the cost does not increase.

[Brief description of the drawings]

1 and 2 are a flow chart of an example of the present invention, FIG.
FIG. 4 is a diagram for explaining this. (1) is a tuner circuit, (11) is a teletext decoder,
(21) is a system controller.

Claims (1)

(57) [Claims] 1. A tuner for receiving a television broadcast signal, an image receiving section for receiving the television broadcast wave received by the tuner, and a television character multiplex broadcast signal superimposed on the television broadcast wave received by the tuner. Decoder, a display unit for selectively receiving the video signal output by the image receiving processing unit and the video signal output by the decoder, and the display based on a synchronization signal supplied from the image receiving processing unit or the decoder. The presence of the television broadcast wave is detected from the synchronization section that performs display synchronization processing in the section and the presence or absence of the synchronization signal supplied to the synchronization section, and the reception channel in the tuner at the time of detection is detected. And a control unit for presetting, and only in a mode in which the video signal output by the image receiving processing unit is supplied to the display unit. In the mode in which the control unit performs the detection for the preset and the video signal output from the decoder is supplied to the display unit, the control unit does not perform the detection for the preset TV character multiplex. Broadcast receiver.